Maxperson
Morkus from Orkus
You missed the second requirement of the point about fudging. If fudging is perfectly acceptable, why do DM's think the players would get angry about it if they knew the DM was doing it. We can hide maps to our heart's content, players won't get angry about it. I've never once heard a player complain that the DM was hiding maps from him. I've certainly heard complaints about DM's hiding fudging.
There's two parts here. One, it's true, is player enjoyment. The other though, is that the players will get actively upset about DM's fudging. DM's are hiding the fact that they are fudging to prevent the players from complaining about it. OTOH, there is absolutely no hiding of the fact that the DM is hiding the map. We know and expect the DM to hide the map from us.
Some players will get upset, others will not. The main reason I don't say anything, though, is that it happens so very rarely that I don't want the players constantly wondering if I am fudging or not. Even though when I do fudge it always raises enjoyment, that wondering, even if they are 100% okay with fudging, will distract them from the game and that distraction will have a negative effect on enjoyment.
Not telling them = a guaranteed net increase in enjoyment. Telling even people who are okay with it = a net decrease in enjoyment, even when the actual fudging increases the enjoyment of that scene.
In fact, DM's who start changing map are equally held in poor regard - it's called rail roading when the DM changes the map in order to force a particular outcome. And it's seen as one of the worst things that DM's can do. If I have two doors out of a chamber, behind one is a very cool monster and the other is an empty room, and I decide that no matter which door the PC's open, the cool monster will be behind that door, that's rail roading, and most players will react very, very negatively to any DM doing that.
If you've been paying attention to the railroading threads, not all railroading is bad. It depends on what it is, what the purpose is, and player buy-in. Not all fudging is bad, either. You are trying to apply absolute standards to something that is not absolute. That's why your arguments break down.